Pre-fill form field with data from prior page in Rails

Question

I recently added Mailboxer to my Rails app and have everything working well.

However, I want to be able to create a new message by clicking a "Message Me" button on a User's page and then have the recipient filled in already (with the User from the prior page) when the form for creating the message loads.

The particular field in question:

<%= select_tag 'recipients', recipients_options, multiple: true, class: 'new_message_recipients_field' %>

And for reference, recipients_options probably won't come into play in this scenario, but it is the list of all Users--which I use primarily when I'm creating a Message from anywhere but a User page--and is defined in my Messages helper

def recipients_options
  s = ''
  User.all.each do |user|
    s << "<option value='#{user.id}'>#{user.first_name} #{user.last_name}</option>"
  end
  s.html_safe
end

And my messages_controller.rb :

def new
end

def create
  recipients = User.where(id: params['recipients'])
  conversation = current_user.send_message(recipients, params[:message][:body], params[:message][:subject]).conversation
  flash[:success] = "Message has been sent!"
  redirect_to conversation_path(conversation)
end

I already have the link to the New Message form on each User page...

<%= link_to 'Message me', new_message_path %>

But I don't know how to pre-fill the recipient in the subsequent form.

Any suggestions for how would I go about this?

Answer 1

Change the link_to code to this:

<%= link_to 'Message me', new_message_path(recipient_id: @user.id) %>

In messages#new action, add this code:

def new
  @users = User.all
end

And, in message form, replace the select_tag with this:

<%= select_tag 'recipients', options_from_collection_for_select(@users, :id, :first_name, params[:recipient_id]), multiple: true, class: 'new_message_recipients_field' %>

I made some changes in recipients select. You can use options_from_collection_for_select method to generate that options instead implement your own helper.

Reference: http://apidock.com/rails/ActionView/Helpers/FormOptionsHelper/options_from_collection_for_select

Answer 2

I am using Mailboxer and I'm able to, from a Listing page, contact the seller.

The user clicks on the contact seller button on Listing page and in on next page the To: form is filled out with seller's name.

I have the same Create method as in your message controller. but in NEW method i have this:

MessageController

  def new
    @chosen_recipient = User.find_by(id: params[:to].to_i) if params[:to]
  end

The contact button on my listing page:

</p>
  <strong>Contact Seller about "<%= @listing.title %>"</strong></br>
  <%= link_to "Send message to #{@listing.user.name}", new_message_path(to: @listing.user.id), class: 'btn btn-default btn-sm' %>
<p>

The NEW message form:

<%= form_tag messages_path, method: :post do %>
  <div class="form-group">
    <%= label_tag 'message[subject]', 'Subject' %>
    <%= text_field_tag 'message[subject]', nil, class: 'form-control', required: true %>
  </div>

  <div class="form-group">
    <%= label_tag 'message[body]', 'Message' %>
    <%= text_area_tag 'message[body]', nil, cols: 3, class: 'form-control', required: true %>
  </div>

  <div class="form-group">
    <%= label_tag 'recipients', 'Choose recipients' %>
    <%= select_tag 'recipients', recipients_options(@chosen_recipient), multiple: true, class: 'form-control chosen-it' %>
  </div>

  <%= submit_tag 'Send', class: 'btn btn-primary' %>
<% end %>

Hope this helps!